Q&A: Cutting & Patching Asbestos Siding

Roofing Under Decks

Q.Occasionally, we run across
asbestos shingles. We sometimes have to cut the
material for a door or window opening. What precautions
need to be taken when cutting through this material?
What is the best way to dispose of a few shingles? Is
this material still available for repairs?

A.Cutting or breaking
asbestoscement board or shingles releases asbestos
fibers into the air. To remove shingles without
breaking, apply pressure near the nail head to
expose the head enough to cut it off with
side-cutters.

If at all possible, asbestos shingles should be
cut with a shingle cutter. Sawing siding panels
with an abrasive saw will release large quantities
of fibers. The shingles can also be scored with a
carbide knife and snapped clean. In either case, a
respirator with a HEPA filter should be worn.

There is considerable controversy over whether
incidental exposure to chrysotile (white) asbestos,
the type used in most residential work, presents
any danger. Research in Europe, primarily in the
United Kingdom, indicates that mild exposure
presents no significant hazard. The blue and brown
types used in commercial and industrial
applications are different minerals, and seem to
constitute a much greater hazard. Extended exposure
to any of the mineral fibers is very hazardous.

The requirements for disposal vary from state to
state. Some states require that the material be
enclosed in a crate or heavy plastic bag, and be
buried in a hazardous waste landfill. Other states
only require that it be bagged and marked, but
buried in the ordinary landfill.

Cement-asbestos board and shingles have not been
manufactured in this country for several years.
Some shingles have been imported from Canada. Now,
imports are prohibited as well. There may still be
some in stock at supply yards, but the stock will
soon be gone.